The Specific Aims of this proposal focus on four key areas of investigation in man. 1. Control by nutrients of the gastrointestinal fasting-fed-fasting motor sequence. 2. Relations among postprandial pressure activity and gastric emptying of liquids and solids. 3. Central nervous system control of postprandial gastric function, specifically through the study of stress-induced perturbations of gastric motility and secretion after meals. 4. Pathophysiological mechanisms involved in functional diseases of the upper gastrointestinal tract. These Specific Aims are integrated into a logical sequence. Starting from a base of established methods we will add certain novel procedures and address outstanding questions related to the control of gastric functions in man. Central to these experiments is the influence of the nature of food (in particular the phsical state and nutrient composition) on gastric motor activity (Specific Aims 1 and 2). These studies are needed to investigate further the effects of stress on the human gut and to address the mediation of these effects through the central nervous system (Specific Aim 3). Finally, we will bring together the preceding projects by investigating possible pathophysiological abnormalities of gastric function and its central control in patients with functional disorders (Specific Aim 4).